The present invention relates to the field of wavelength-division-multiplexed light-signal routing networks.
Dense wavelength-division multiplexing (WDM) is an important aspect of advanced long-distance fiber-optic communications networks, especially telecom and antenna remoting networks. Each of the several network fibers transports eight or more independent high-speed optical-wavelength-encoded signals. Voice/video/data signals are encoded on different, but closely spaced, wavelength "carriers" near 1550 nm or 1300 nm. A key component for signal routing and dynamic reconfiguration of the network is the electro-optical WDM crossconnect, an integrated optical switching component that interfaces with M fibers at its input and M fibers at its output. Prior art exists on such crossconnects; however, the prior-art thermooptic silica versions have large area and millisecond response times, the unamplified III-V semiconductor versions have crosstalk greater than -22 dB, and the fast LiNbO.sub.3 versions require actuation voltages greater than 5 volts. There are unmet needs for smaller-area, lower-crosstalk, planar, nonblocking electrooptic crossconnects having restoration times less than one nanosecond and switching voltages less than 5 volts. Other unmet needs of such systems relate to low cost, low optical insertion loss, and being monolithic with commercial electronics. The crossconnect components in this invention offer most of these desired features in one compact chip.